Ecological Study Links Antiretroviral Scale-Up to Regional HIV Reductions in Africa

Between 2010 and 2022, the expansion of antiretroviral therapy coverage across 38 sub-Saharan African countries was associated with substantial yet regionally heterogeneous declines in HIV incidence and mortality, according to a longitudinal ecological study. During this twelve-year study period, overall antiretroviral therapy coverage increased from 22% to 75%. Concurrently, observed HIV incidence decreased by 65% (95% CI 60–70), observed HIV mortality declined by 72% (95% CI 68–76), and observed HIV prevalence fell by 33% (95% CI 30–36), with overall percentage changes estimated using country-level bootstrap resampling.

To assess these trends across a continent that carries two-thirds of the global HIV burden, the researchers analysed 494 country-level observations from 38 countries using data obtained from UNAIDS, the World Bank, and the UNDP. The analysis employed fixed-effects panel regression models adjusting for demographic, economic, and health system covariates, with calendar-year fixed effects included to control for secular trends. Regional interaction terms using East Africa as the reference evaluated effect heterogeneity, and all models incorporated country-level clustered standard errors. Region-specific associations were calculated as the sum of reference and interaction coefficients, with confidence intervals derived from the variance-covariance matrix.

The regression estimates revealed marked regional variation in statistical associations between treatment expansion and epidemiological outcomes. In East Africa, a 10% increase in antiretroviral therapy coverage was associated with a 1.6% reduction in HIV incidence (β=-0.16, 95% CI -0.24 to -0.08) and a 4.2% reduction in HIV mortality (β=-0.42, 95% CI -0.49 to -0.35). Significant but attenuated associations were documented in other regions: West Africa exhibited a 0.2% reduction in incidence (region-specific β=-0.02, 95% CI -0.04 to 0.00) alongside a 2.6% reduction in mortality (region-specific β=-0.26, 95% CI -0.30 to -0.22). Reductions in mortality associated with each 10% coverage increase were estimated at 2.1% in Southern Africa (region-specific β=-0.21, 95% CI -0.25 to -0.17) and 3.2% in Central Africa (region-specific β=-0.32, 95% CI -0.38 to -0.26).

The association with HIV prevalence was modest, showing a 1.0% reduction per 10% increase in coverage in East Africa, and was substantially modified by the incidence-to-mortality ratio. A model-based counterfactual estimate indicated that had coverage remained at 2010 levels, approximately 1.2 million (95% CI 1.0–1.4) additional deaths may have occurred across the study timeframe. The authors emphasized that these results represent longitudinal ecological associations rather than direct causal effects, concluding that prevalence trends should not serve as standalone measures of programme success and that regionally tailored strategies supported by sustained health system investment remain essential.

Subject of Research: Antiretroviral therapy coverage and regional HIV outcomes in sub-Saharan Africa

Article Title: Regional heterogeneity in the association between antiretroviral therapy coverage and HIV epidemiology in Sub-Saharan Africa: a longitudinal ecological study of 38 countries (2010–2022)

Article References: Bekolo, C. E., & Yonta, D. E. (2026). Regional heterogeneity in the association between antiretroviral therapy coverage and HIV epidemiology in Sub-Saharan Africa: a longitudinal ecological study of 38 countries (2010–2022). Archives of Public Health. https://doi.org/10.1186/s13690-026-02094-9

Image Credits: AI Generated

DOI: 10.1186/s13690-026-02094-9

Keywords: HIV epidemiology, antiretroviral therapy, sub-Saharan Africa, longitudinal ecological study, HIV incidence, HIV mortality, health systems, public health, Regional, heterogeneity, association, between